Numerous types of adhesive film dispensers are currently in use ranging from relatively simple single use dispensers as shown in Corbo, et al., U.S. Pat. No. 4,961,525 to devices used by bulk mailers of packages such as Clements U.S. Pat. No. 6,296,033.
The latter category of dispenser is characterized by a pistol grip handle having a bulky roll of tape above it and a dispensing mechanism, including cutting blade, jutting out at about 90° or greater from a plane which passes through the handle and centerline of the tape. This type of dispenser features a triangular orientation of tape, handle and cutting blade. Other examples of such “pistol grip” adhesive film dispensers are described in U.S. Pat. Nos. 6,491,082; 6,478,067; 6,296,033; 6,257,298; 6,098,690; 5,954,916; 5,849,144; 5,456,790; 5,393,367; 5,110,401; 4,804,437; 4,818,329; 4,762,586 and other patents.
Pistol grip dispensers, however, are not ergonomic devices. They are typically top heavy with much of the weight in the forward part of the device, outside the axis of the handle. This tends to pull the device forward when held by applicator, adding to wrist and arm strain of the user. In addition, the angle of adhesive film application from pistol grip dispensers is awkward. More specifically, the pistol grip dispenser must be rotated through an arc of about 60–90° each time the adhesive film is applied to a surface. To cut the tape, the dispenser typically must be rotated another 30–60° to force the cutting blade into severing contact with the film or tape to be cut. See FIG. 1 and column 3, lines 60 et. seq. of U.S. Pat. No. 6,296,033.
Existing adhesive film dispensers can also inflict other harm on users, for example, cuts arising from user contact with the cutting blade. Several different approaches for limiting such harm appear in existing patents.
Among those approaches is that described in Clements U.S. Pat. No. 6,296,033 which discloses a removable guard formed from a pliable material which is removably attached to, and extends beyond, the cutting blade. The extended length of the guard beyond the outer edge of the cutting blade limits impact of the blade on objects and the user. (See FIG. 3 and column 3, lines 28–40). The Clements patent also discloses use of a less pliable guard which is scored along a bendline to form a resilient hinge (See column 3, lines 40–44). The guard is moved out of its guarded position over the serrated blade by the tape as it is drawn off the tape roll and toward contact with the blade. The tape pulls the shield away from the blade to facilitate the latter's penetration of the tape. (See FIG. 4 and column 3, lines 60, et seq.).
Another approach to shielding a user from the cutting edge of a tape dispenser is disclosed in Chen, et al. U.S. Pat. Nos. 5,456,790 and 5,393,367. These patents disclose a rigid pivoted shield that is normally biased into a protective position over the cutting blade. The shield is pivoted out of its protective position when the tape dispenser is tilted to dispense tape, thereby allowing cutting engagement of the blade with the tape (See FIGS. 5–6 and column 4, lines 42–47 of the '790 patent).
Other patents approach the problem of sharp cutting blades with mechanisms that retract the blade until it is needed to cut the tape. In Chung, et al. U.S. Pat. No. 5,641,377, a hand held dispenser employs a mechanism which extends the blade when pressure is applied on a pivoting “wiper” extending from the body of the dispenser (See FIGS. 2–3 and column 4, lines 49 et seq.). A very similar arrangement for a retractable blade is disclosed in Tang, et al. U.S. Pat. No. 5,849,144.
U.S. Pat. No. 4,818,329 issued Apr. 4, 1989 to Tutas, et al. discloses a rigid, spring-biased movable guard over a cutting blade mounted on a rotatable shaft which is normally spring biased to cover the blade but can be rotated out of its covering position when the dispenser is rotated into position to dispense tape (See FIGS. 2–3 and column 7, lines 2049).
Yet another approach to limiting contact with a dispenser blade is illustrated in commonly assigned U.S. Provisional Application Ser. No. 60/425,006 filed Nov. 9, 2002. This application describes a frame on which a roll of tape is rotatably mounted. A shield extending from the frame and parallel to the cutting blade minimizes user contact with the blade. The shield either extends beyond the edge of the blade or in close proximity thereto, thereby protecting the user.
Another issue with other adhesive film dispensers is the management of the film after it is cut. If the loose end of film, after it is cut from the roll, is not properly managed the sticky side of the tape can double over on itself with consequent detriment to future application of tape on surfaces to be taped. Or the loose end of the film or tape can rewind onto the tape roll before the dispenser can be used. One approach to management of loose ends of tape or film after being cut from the roll is multiple tabs surrounding the loose end of the tape as it is unwound. Suhr U.S. Pat. No. 4,944,720 discloses such tabs (reference number 40 in FIG. 2) whose function is described at column 1, lines 33–43. Guide rollers in FIG. 2 of Chen U.S. Pat. No. 6,152,398 are also designed to hold the loose end of tape in place so that it may be easily applied to the next article to be taped (column 2, lines 11–15).